Sorry about the 12v to 5v in the picture - that was just a quick example, it wasn't ment to be accurate.
Let me explain what exactly I'm doing.
I'm making a circuit to attach to a drum on a drumset that can sense how hard the drum has been hit and turn on a 12v light accordingly to how hard the drum is hit. I am making a test circuit using a 9v and a LED.
I have a Piezo - just a raw disc with the soldered wires on it. It is attached to the bottom of the drum skin - bronze side touching.
Next I have the 9v battery's positive terminal connected to the red wire of the piezo and the black wire of the piezo is conncted to a resistor which inturn goes to my LED and finally goes back to the battery.
It works fine. I hit the drum lightly - the LED dimly turns on. I hit it hard - the LED is much brighter, but not fully bright.
I tested the circuit at a few points and found a drop in voltage after the piezo. I then assumed I must have mismeasured the voltage or something. So, I tried re-mesuring the voltage directly before and after the piezo.
Before the piezo, the voltage is 8.34v (coming straight from the battery of course) and directly after it I measured from 0 - 6.83v.
0v not doing anything to the piezo
6.83v after hitting the drum skin.
Is this normal? Am I going about it all wrong? I'm just experimenting and having fun, my apologies if I have mangled any more terminology or theories.
I think what I am looking for is a transistor. I misunderstood what a transistor did. The book I read gave me a different Idea of what it can do.
Thanks again. Hope this helps